The Mouse Auditory Testing Core (MATC) Facility was established in July 2011. The MATC assists the Principle Investigators of the NIDCD and their collaborators with auditory testing in mice, including experimental design, data collection and analyses, and preparation of auditory test data for presentation or publication. Dr. Fitzgerald trains investigators in auditory testing techniques. The facility also assists with protocols that require noise exposure. Two physiological measures of auditory function are employed at the MATC: the auditory brainstem response (ABR) and distortion-product otoacoustic emissions (DPOAEs). The ABR is an evoked potential that can be used to estimate hearing thresholds. The ABR is measured by placing electrodes on the scalp and recording the potentials generated by the auditory nervous system when a sound is repeatedly presented to the ear. DPOAEs are soft sounds that are recorded in the ear canal and can be used to screen for hearing loss or to evaluate inner ear (cochlear) function. The presence of DPOAEs indicates normal function of outer hair cells in the inner ear. DPOAEs are measured by placing a small probe containing two speakers and a microphone in the opening of the ear canal. Two tones are played simultaneously to the ear and the DPOAEs produced by the ear are recorded by the microphone. In the third year of operation, 17 investigators from the NIDCD have been trained in ABR and DPOAE test techniques and interpretation. Dr. Fitzgerald collaborated on 16 projects conducted in six NIDCD labs and on one project for a lab in the NICHD. Dr. Fitzgerald was a co-author on two manuscripts published this past year and on one paper currently in press. Dr. Fitzgerald assisted with planning auditory test protocols, collection of DPOAE and ABR data, and/or analysis of auditory test data for the following projects: Chien Lab (NIDCD): Dr. Fitzgerald collaborated on three ongoing projects investigating the use of gene therapy to remediate hearing loss. Kevin Isgrig (Biologist) and Dr. Bovey Zhu (Special Volunteer) were trained in DPOAE and ABR testing and interpretation. Cunningham Lab (NIDCD): Dr. Fitzgerald collaborated on a project examining the use of moderate noise exposure to reduce the hearing loss caused by the ototoxic drug cisplatin. Dr. Fitzgerald also assisted with set-up and calibration of noise exposures for this experiment. Dr. Fitzgerald consulted with the Cunningham Lab and Audiology Unit regarding pilot projects examining ABR wave amplitudes in humans. Andrew Breglio (NIH Oxford-Cambridge Scholar), Aaron Rusheen (Post-Bac IRTA), Dr. Jasmine Saleh (Post-Doctoral IRTA Fellow) and Dr. Soymen Roy (Visiting Post-Doctoral Fellow) were trained in DPOAE and ABR testing and interpretation. Friedman Lab (NIDCD): Dr. Fitzgerald collaborated on six projects in the Friedman lab. In most cases, the objective was to establish the auditory phenotype for a particular mutant mouse strain. Projects included (1) Myosin15 mutant mice for Dr. Jonathan Bird (Visiting Post-Doctoral Fellow), (2) Hgf mutant mice for Dr. Julie Schultz (Biologist), (3) Clpp mutant mice for Dr. Meghan Drummond (Post-Doctoral IRTA Fellow), and (4) Ildr1 mutant mice for Dr. Inna Belyantseva (Staff Scientist). Dr. Fitzgerald assisted in manuscript preparation for the project on Ildr1 mice (in press). Dr. Fitzgerald assisted Dr. Robert Morell (Staff Scientist) with two projects: one on novel GM1714 mutant mice and one on Grhl2 double mutant mice. Dr. Fitzgerald assisted with set-up and calibration of noise exposures for Dr. Morell's experiments. Stacey Cole (Post-Bac IRTA), Dr. Drummond, Joseph Duda (Student IRTA), Eva Morozko (Post-Bac IRTA), Dr. Schultz, Brittany Whitley (Post-Bac IRTA), and Elizabeth Wilson (Biologist) were trained in DPOAE and ABR testing and interpretation. Griffith Lab (NIDCD): Dr. Fitzgerald collaborated with Dr. Ayako Nishio (Visiting Post-Doctoral Fellow) on three projects investigating Slc26A4 mutant mice. Dr. Kiyoto Kurima (Staff Scientist), Jane Rose (Student IRTA), and Dr. Nishio were trained in DPOAE and ABR testing and interpretation. Kachar Lab (NIDCD): Dr. Fitzgerald assisted with manuscript preparation for Dr. Taro Fujikawa's (Visiting Post-Doctoral Fellow) project on the kainate receptors of the outer hair cells and their afferent terminals. The manuscript was published in Hearing Research in August 2014. Kelley Lab (NIDCD): Dr. Fitzgerald collaborated on Dr. Thomas Coate's (Post-Doctoral Fellow) project investigating mice lacking the Nrp1 and Nrp2 genes and served as a co-mentor on his K99 grant. Dr. Coate was trained in DPOAE and ABR testing and interpretation. Burgess Lab (NICHD): Dr. Fitzgerald collaborated a project for Sadie Bergeron (Post-Doctoral IRTA Fellow) investigating the auditory phenotype in the Gsx1KO knock-out mouse. In January 2014, the MATC moved from the 5 Research Court facility to the Porter Neuroscience Research Center on the NIH campus. In June 2014, the MATC participated in the first Earssentials training course, a week-long, NIDCD-wide course designed to expose new trainees to the various areas of study and the techniques used in the labs at the NIDCD. Ten students from 4 labs in the NIDCD and one student from outside the NIH (JMHI) participated in a laboratory training exercise on DPOAE and ABR measures in mice. Assembly of a new system for measurement of vestibular sensory evoked potentials (VsEPs) began in the summer of 2013 and is in progress. VsEPs are recorded by placing electrodes on the scalp, similar to an ABR, and recording the electrical potentials generated by the vestibular nervous system in response to linear movements of the head.